In a conventional nailing machine, a cylindrical ejection opening is formed in a nose portion. In a rear side part of the ejection opening, an opening through which connected nails are supplied into the ejection opening is formed. A foremost one of the connected nails supplied from the opening into the ejection opening is hammered out from the ejection opening by a driver reciprocatively driven in the ejection opening. The inside diameter of the ejection opening of the nose portion is set at a maximum diameter of a head portion of a largest size one of nails used in the nailing machine. The head portion of the nail, which is hammered out from the ejection opening by the driver, is guided by the inner wall surface of the ejection opening. A tip end portion of the nail is in a free condition. When the nail supplied into the ejection opening is hammered by the driver, the tip end portion of the nail may be inclined by resistance, which is caused by disconnecting the nail from the subsequent one of connected nails, to the rear side in the ejection opening. Thus, the nail may be hammered out in such a state that the tip end portion of the nail is inclined rearwardly, and may fly out from an opening, opened rearwardly from the ejection opening, to the rear of the nose portion.
To solve this phenomenon, a conventional nailing machine is configured so that a slope, which is rearwardly and upwardly inclined, is formed integrally with the bottom portion of an opening, which is formed to be opened rearwardly and to introduce a nail to a cylindrical ejection opening. The tip end portion of the nail hammered out rearwardly contacts with the slope to thereby guide the tip end portion of the nail into the ejection opening. Thus, the conventional nailing machine prevents a nail, which is hammered out from the ejection opening by the driver, from flying out to the rear of the ejection opening. However, the tip end portion of the nail, which is hammered by the driver at the head portion thereof and is discharged from the ejection opening, can freely move in the ejection opening. Thus, sometimes, the nail is freely inclined, so that the nail is hammered out in an inclined state from the ejection opening, and that the nail is tiltingly driven into a member. Especially, in the case of a nail that is small in diameter of the head portion and that is short in length of a shank, an angle of inclination of the nail in the ejection opening is large. This increases tendency to drive a tilted nail into a member.
Further, JP-Y-07-027090 proposes the following technique. Paired holes are formed in an end part of a cylindrical nose portion, in which an ejection opening is formed, to face a cylindrical surface. Paired claw members respectively urged by springs, which cause tip end portions of the claw members to enter the ejection opening through the holes, are provided on the nose portion to be able to swing. The bottom surface of the head portion of the nail is held by the claw members to thereby bring the top surface of the head portion of the nail, which is driven out by being hammered with the driver, into intimate contact with the bottom surface of the driver. Also, the shank of the nail to be hammered is aligned with a line parallel to an axis line of the nose portion. Consequently, the tip end of a nail is placed at the center of the ejection opening, so that the nail is hammered out from the ejection opening.
Meanwhile, in a nailing machine adapted so that a piston is driven by using compressed air as a power source, and that a nail supplied in an ejection opening is hammered out by a driver connected to the piston, a reaction to an operation of actuating the piston by using compressed air is caused in a main body of the nailing machine. This causes a phenomenon that the nailing machine is reacted in a direction opposite to a direction in which a nail is hammered. Thus, simultaneously with the reaction of hammering out the nail from the ejection opening, the end portion of the nose portion frontwardly moves as a reaction. There is tendency that the end portion of the ejection opening is frontwardly moved by the reaction of the nailing machine when a nail is driven into a member to be nailed in a state in which the tip end of the nail is placed on a back side of the bottom portion of the ejection opening, or in which the tip end of the nail is placed at the center of the ejection opening. Also, a nail is sometimes driven thereinto in a state in which the head portion of the nail is frontwardly inclined.
As described above, the shank of the nail to be hammered is aligned with a line parallel to the axis line of the nose portion in by the pair of claw members pressed by the springs in the aforementioned conventional nailing machine. However, in a case where nails are driven into nail hammering holes formed in predetermined places of a metal building member, since the nail is driven by placing the tip end of the nail at the center position of the nose portion, this conventional nailing machine has drawbacks that it is difficult to align the center position of the end portion of the ejection opening of the nose portion with each of the nail holes. Thus, it is impossible to drive a nail into the nail hole of the metal building member.
Further, in the conventional nailing machine, in which the claw members adapted to enter and exit the ejection opening are formed, a nail hammered out tiltingly from the opening formed in the rear side of the nose portion cannot be guided into the ejection opening. Thus, it is necessary to form an additional structure adapted to guide the tip end of a nail tilted rearwardly.